Schizophrenia as Terrain Fragility: A Terrain–Timing Model of Developmental State-Transition Vulnerability

Why does schizophrenia aggressively cluster around specific developmental windows like late adolescence? Rejecting single-cause neurochemical paradigms, this paper applies the framework of Terrain Fragility—a state of compressed adaptive reserve where networks function normally under low demand but collapse catastrophically during simultaneous cross-system remodeling. The model treats adaptive myelination constraints and axonal conduction velocity dispersion as the key structural bridges translating sub-cellular terrain distress into macro-scale cortical neural phase desynchronization, integrating sleep, circadian, and endocrine data.